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Building system from ground up ... and option two for future expansion


sweet rolls

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Greetings all, 

long time reader - first time poster. 

wanted to get some sober head clarification. (i live in rented house and cannot put panels on)

have two thinking paths
1) - Shorter term
2) - Longer term

1) would entail installing smaller/cheaper system that would serve as backup for load shedding.
i was considering getting Growatt SPF500es and bypass non essentials like geyser (gas stove already installed)
for battery i was thinking 3x pylontech US3000C .... or FreedomWon 10/8 (or 2x E towers)

what would you say pros/cons of the pylon vs freedom be? i realise there is cost differential to begin with. 

as i mentioned above, this would be "cheaper" system by value of cheaper inverter... even though battery an be expanded/added later... 

2) buying now for the future options... 
getting sunsynk 8kw inverted ... which is triple the cost. but opens up future potential of larger loads, more panels and better management of everything. assuming similar battery starting set up right now. 

the difference in inverters adds about 1 pylon :) which is helpful. 

My main question is... more about batteries i guess


if you were to start now and go forth for the next 5 years... be it 5kw or 8kw inverter ... which direction would you lean on/recommend in terms of batteries. 

I may have to go with growatt for now and then either add a second one for more load availability... and add panels if possible. (i do not foresee me "selling" any power to the city ... ever... so grid tied inverted is not really something that i would think i need)
OR
buy sunsynk now... and be poor :)

side note - my general power requirements are low - 5kw would suffice and 8kw would be more than plenty. 

would appreciate any help/suggestions/ideas you might throw my way. 

Thank you in advance

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1 hour ago, sweet rolls said:

for battery i was thinking 3x pylontech US3000C .... or FreedomWon 10/8 (or 2x E towers)

what would you say pros/cons of the pylon vs freedom be? i realise there is cost differential to begin with. 

Both are good quality batteries. 

The FW 10/8 is C1 and so you can draw a full 200A from it when you need to (assuming your inverter permits this).

The 3000Cs I see being advertised right now are 74Ah batteries and you can draw 74A for 15 seconds. So you could deal with 210A loads for short periods (again, inverter permitting).

The 10/8 is self contained. You don't need any racks nor cable kits. I used to have a different brand of battery, and an unstable system. The installer recommended a switch to a 10/8. Since then the system has been stable. So batteries make a difference.

The 2*e-tower also gives you a 200A draw. I don't have any experience with that battery. I doubt it's the same internals as the 10/8 otherwise why would they market both?

One advantage of having a stack of batteries is that if something starts playing up and needs to go to the dealer for tests, you can retain some of your backup capacity.

A general observation: Look at the combination of battery & inverter. Check that they are compatible. EG if you buy Revov it's only really compatible with Sunsynk and Victon. Just about every inverter on the planet knows how to talk to Pylontechs. Sometimes the intelligence is built into the BMS. My inverter has no built-in settings for Freedom Won (it does for various combinations of Pylontech), but when the guy installing the FW plugged in the comms cable the BMS very quickly took over and changed settings on the inverter.
 

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Another thing. 10kWh of battery should be more than enough to get you through a load shed, but long term, with charging it from PV during the day, the battery will get you through the night with a bit of management and discipline on your side.

I've given the example before:
My 10/8 was at 65% at 6:00 today. At that time the heat pump kicks in. After that run the battery was at 51%. We had load shedding due to start at 08:00. By 08:00 I was starting to get some PV and the battery was at 53%. Enough to get through a 2 hour shed. And then, on a sunny day, I'd still have something in hand if there was a delay getting the power back on.

So with a 5kWh battery I'd have got through to 6:00 with 15%  1.5 kWh in hand, but wouldn't have had the same backup power going forward. Or I'd have had to use more grid power during the night so as to leave myself some protection in the morning.

More battery gives you greater flexibility and security. So, IMO, you are on the right track going for 10kWh from the start.

I'd give serious consideration to getting the Sunsynk now. Less hassle going forwards. You don't have to remove Growatt, wire in the Sunsynk and then sell the Growatt at a loss. 

Figure out what loads happen when. When you don't have panels this is not such a consideration, but once  you do, you want to do as much with PV during the sunlit hours as you can, and reduce the draw from your batteries overnight. 

My cousin in the UK recently got solar (subsidised by her town council, lucky her). She told me that before solar she used to leave lights burning all day, had a radio or TV on in just about every room etc etc. Now she's an electricity miser and makes sure nothing unused is left on, and she only turns on the washing machine when she knows the sun is beating down on her panels.

Edited by Bobster.
was an error in the numbers
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56 minutes ago, Bobster. said:

Another thing. 10kWh of battery should be more than enough to get you through a load shed, but long term, with charging it from PV during the day, the battery will get you through the night with a bit of management and discipline on your side.

already living smartly :) learned very quickly from not having power :)

More battery gives you greater flexibility and security. So, IMO, you are on the right track going for 10kWh from the start.

I'd give serious consideration to getting the Sunsynk now. Less hassle going forwards. You don't have to remove Growatt, wire in the Sunsynk and then sell the Growatt at a loss. 

then perhaps a good question would be to ask about sunsynk 10kw batterie Vs FW 10/8. How would that play into decision:) i think sunsynk gives you 10y warranty on inverter with used with their battery... fwtw

My thought about Pylons was exactly that... 3 pieces ... vs ONE ... one goes kaboom... i have no power.... in Pylon'se case... i am still ok 

thank you for sharing your thoughts

self contained looks very nice and neat i have to admit. 

 

Edited by sweet rolls
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